Antibiotic Resistance Tracking

March 6, 2019 — 

Ever since the Centers for Disease Control and Prevention released its 2013 report, "Antibiotic Resistance Threats in the United States" — which states that each year at least 2 million people get an antibiotic-resistant infection, and at least 23,000 people die — there has been a concerted effort to track antibiotic resistance. However, while there have been significant endeavors to track antimicrobial resistance in human health and food safety, not as much work has been done at the livestock level. [Source: National Hog Farmer 4 March 2019 by Ann Hess]

So, when the updated Veterinary Feed Directive went into effect Jan. 1, 2017, the 40-member veterinarian team at Pipestone Veterinary Services knew it was a prime time to see if antibiotic use in swine contributed to antimicrobial resistance over time. The Pipestone team examined 4,163 swine clinical case submissions over 15 years from the veterinary diagnostic labs of South Dakota State University, Iowa State University and the University of Minnesota from 2002 to 2017.

Based on whether bacteria recovered from these cases were sensitive (antibiotics would work) or resistant (antibiotics would not work) to the antibiotics in the food animal antimicrobial testing panels across these three labs, a resistance index was calculated and plotted over the 15-year period.

"This novel approach to tracking antibiotic resistance from swine cases seems to indicate that despite the use of antimicrobials over a prolonged period of time, the overall level of resistance has not changed," says Joel Nerem, DVM, director of health at Pipestone Veterinary Services based in Pipestone, Minn.

"Calculation of the index will continue as new cases are added to the database. Stay tuned as we continue to learn and share."

The antibiotic resistance tracking project is only one area Pipestone Veterinary Services is conducting in antimicrobial stewardship. The team is also examining how antibiotic use on farm is reflected in resistance for human pathogens.

Scott Dee, DVM, director of research at Pipestone Veterinary Services, has been working on developing a means of how to measure pathogens of food safety and human health at the farm level. Since the National Antimicrobial Resistance Monitoring Service is already accepted by the government and the national medical community, Dee used those standards to measure the level of four specific bacteria, known to cause food-borne illness in people: E coli, Salmonella, Enterococcus and Campylobacter. Unlike tracking antimicrobial resistance (AMR) at the veterinary level, where one or two sick pigs out of 2,400 are posted and a few samples sent to a lab, Dee says he wanted a more comprehensive, representative sample of the population and its environment.

After collaborating with the Veterinary and Biomedical Sciences Department and Food Safety Microbiology Laboratory at South Dakota State University, Dee has developed a protocol to sample both live animals prior to marketing, and their environments. In addition, the group has mimicked the exact antimicrobial susceptibility panel used by NARMS, so now group members can start to track resistance patterns across the four bacteria.

"To make a long story short, our methods have proved to be accurate and repeatable, not only in swine environments but across alternative environments, such as human wastewater treatment plants, playground dirt and companion animal facilities," Dee says. "We can routinely detect our four NARMS bacteria and determine their level of AMR."

Pipestone has also started an antibiotic resistance research project with National Pork Board funding. Carissa Odland, a veterinarian with Pipestone and a master's degree candidate at the University of Minnesota, is heading up that project, which will place pigs on feed and then expose them to various levels of antibiotic therapy. She will then track and collect samples of antibiotic resistance for the lifetime of those pigs in a brand-new Biological Safety Level 2 facility to help better control environment and maintain the isolation of these groups. The research project will follow those pigs all the way to harvest.

"We are very excited about this project and the funding that Pork Board and others have put into it to help us better understand what antibiotic resistance looks like at the farm level as it is related to pathogens of human interest," Nerem says.

Producers doing their PART

In addition to its antibiotic resistance investigations, Pipestone Veterinary Services has also launched its own tracking program at the producer level: the Pipestone Antibiotic Resistance Tracker.

"Being a company owned by veterinarians, we felt it was very important to show leadership in the area of antibiotic stewardship, because it ultimately starts with the veterinarian direction and recommendations -- so we launched PART to increase that visibility," Nerem says.

Two years later, more than 150 of Pipestone's independent producers, representing 5 million weaned pigs and 3 million market hogs, have voluntarily signed up for PART. This grants them access to a web-based tracker providing comprehensive antibiotic use (grams per head and cost per head), internal and external benchmarking, and a quarterly veterinarian review and consultation.

An interactive, web-based tool, PART not only tracks resistance over time and benchmarks antibiotic use by farm, Nerem says, but also serves as a platform to inform consumers, media and policymakers about the responsible antibiotic use practices being conducted on farms. Solely funded by Pipestone and producer subscription fees, PART uses the same metrics that NARMS uses for human resistance.

Nerem says it's also important to note that PART is focused on tracking antibiotic resistance and demonstrating responsible antibiotic use practices, and is not about reducing antibiotics.

"I think one thing we were very cognizant of was that we didn't want to create a race to the bottom on antibiotic use. We think that is bad for the pig," Nerem says. "If, suddenly, the producer is now more concerned about how we can get lower than our neighbors, we don't necessarily think that is a good thing. It's about responsible use, and it's about measuring. If we are not measuring, we are not being responsible."

By monitoring and measuring antibiotic use on-farm, PART gives the subscribing producers a record and review of their use, as well as an opportunity to respond.

Record

PART records antibiotic use information by compiling water-soluble and injectable information from Pipestone Veterinary Services, as well as feed-grade medical information from the producer's feed mill.

Producers who participate then have their own log-in identification and can see how antibiotic use is measured, the form of administration, the drug type, classification and its relevance to human medicine.

Review

PART then takes all of this information and displays it in easy-to-understand graphs, allowing the producer to review antibiotic use by site and group, make cost comparisons, and observe anonymous benchmarking against other producers and resistance patterns.

"We can show a producer where they fit within our benchmark compared to other producers and medication practices, and can also show where they track over time compared to the rest of the producers participating," Nerem says.

Respond

Now, with a better understanding of antibiotic use, Nerem says the producer can respond by working with his or her veterinarian to decide what changes in antibiotic use may improve herd health, performance and the bottom line.

"In the end, we know antibiotics are just a piece of the comprehensive approach we take to managing and improving the health of animals," Nerem says.

"So, when we talk about a comprehensive approach to health at Pipestone, we are talking about how are we designing facilities to raise pigs, what are the biosecurity practices we are putting in place to keep disease out, what's the disease status, and which diseases are we going to choose to eliminate," he adds."

Nerem says Pipestone team members are very strong believers in disease elimination. They also recognize that there are more components to eliminating disease than antibiotics alone.

Ventilation, air filtration and nutrition are just as important to the health status of the pig.

"Antibiotics and vaccination are important, but they are not the whole picture, either," Nerem says.

Nerem says the VFD requirements only helped demonstrate that further.

"I think with the requirement now for VFDs and the topic of antibiotic use being at the forefront of our customers' minds, we have had customers now asking for and supporting disease elimination programs, particularly mycoplasma pneumonia at the breeding herd level," Nerem says.

"A lot of the feed-grade medication that's been used in our customer base has been because of respiratory disease. I think that bringing the feed-grade use to the forefront or in the spotlight has helped usher that in, which I think again is good for the pig and good for everyone. It's better to eliminate disease than treat it."

Keeping antibiotics in the arsenal: Pigs can still get sick

When the new Food and Drug Administration antibiotic guidance rules went into effect Jan. 1, 2017, it was a good reminder to all pig farmers that antibiotic stewardship is very important, and to strive for reduction in use when possible.

Brad Greenway says his farm's use of antibiotics has decreased, but it's not something he plans to take out of the toolbox anytime soon.

"The thing we have found on our farm is, we need to have antibiotics as a tool," the Mitchell, S.D. pork producer says. "I think every producer does their very best to use all the preventative measures to keep pigs healthy, but sometimes they still get sick."

The 2016 America's Pig Farmer of the Year winner is just one of the 150 Pipestone independent producers who signed up to take part in the Pipestone Antibiotic Resistance Tracker program.

Participating in PART

In addition to the comprehensive antibiotic monitoring system, the Greenways have built a solid working relationship with their veterinarian through participation in PART. The veterinarian not only oversees the pig health program at their farm, but also at the 13 other Davison County farms that cooperatively own Bluestem Family Farms. Managed by Pipestone Veterinary Services, the sow farm supplies pigs for the owners' respective pig farms in the area.

"We know exactly what the health status is at the sow barn, our source of the baby pigs, and what to look for," Greenway says. "I think that has really been a plus the last couple years — really paying attention to that and being prepared, knowing the health status of the pigs coming on to our farm, and then having that relationship with our veterinarian to continue that protocol."

When a new batch of pigs arrives at either of the two Greenway 2,400 wean-to-finish barns, they are accompanied with a current health status report and veterinarian treatment and care recommendations. Each week, the Greenways also report back any mortalities and challenges they see. That way, the whole group that gets pigs from the sow barn can be prepared.

"It's that communication amongst the whole group that I think has really been a strong point and helped us learn from each other," Greenway says.

Biosecurity and nutrition

Besides the increased communication with their farm's veterinarian and the other farms, Greenway also credits their heightened biosecurity efforts for decreased antibiotic use. Also, having their own feed mill on site reduces outside traffic coming to the farm.

The Greenways also ensure the barns are comfortable when pigs come in to keep stress down. They work closely with their swine nutritionist, making sure the diets are balanced and adjusted as the pigs grow.

"From biosecurity to having the barns prepared, ready and comfortable, to having the right feed — that goes a long way in preventing disease," Greenway says.

Pigs can still get sick

There are a lot of different ways to raise pigs -- whether they be outdoor, niche or conventional — and there is room for everybody. With the increased consumer demand for antibiotic-free production, Greenway says, some farmers are able to provide that.

"I think the message to consumers is if we do use antibiotics, it's done responsibly, under the advisement of our veterinarians. We document use, make sure we always follow the labels, and we follow antibiotic withdrawal times before delivering the pigs to market," Greenway says.

It's a commitment the Greenways have never faltered from, even with all the extra efforts they have made over the last two years to try to lower their antibiotic use on-farm.

"As a trend over the last two years, we have seen a decrease; but as producers we need to recognize each group is different, each stress challenge is different, and things can happen," Greenway says. "Be prepared for that, and make sure that we continue to have antibiotics as a tool when needed — because walking into a barn and seeing pigs challenged is disheartening to any pig farmer."